U.S. Pat. No. 4,400,475 the entire disclosure of which is incorporated herein by reference describes the preparation of polyurethane foam compositions by reaction between a polyisocyanate and a carbohydrate in aqueous media in the presence of other reagents such as catalysts, surfactants, and other components normally used in polyurethane foam production.
More specifically, the patent describes the production of polyurethane foams which may contain fire retardants in on site foam uses such as packaging and retrofit building insulation. The reactants are provided in two separate mixtures. The first contains at least the polyisocyanate, the second contains at least the carbohydrate and the polyurethane foam producing catalysts. These mixtures, for convenience have been called, respectively, the A-side and the B-side.
Preferred embodiments of the B-side contain amine catalysts. It has been found that such compositions may have a relatively short shelf life due to inactivation of the catalyst. With some compositions the shelf life may be quite short, for example, up to about three months. If the A-side and the B-side are utilized shortly after preparation, short shelf life is little or no problem. However, if the mixtures are to be stored for intermittent use a short shelf life is unacceptable.